The overall objective of this project, "Clinical Studies of Therapies for Virus Infections", is to conduct clinical trial/studies to evaluate promising therapies for the treatment of acute and chronic human viral diseases that are deemed medically and scientifically important by the National Institute of Allergy and Infectious Diseases. This program will facilitate advances in clinical antiviral therapy by rigorously evaluating the efficacy and safety of new therapeutic regimens for serious viral diseases in adult and pediatric immunocompromised and immune competent patient populations. In addition, data on disease natural history, pathogenesis and epidemiology will be conducted and evaluated in order to enhance our understanding of viral disease processes and to help in deciding new strategies for future trials.